Effects of Paclitaxel and Quizartinib Alone and in Combination on AML Cell Line MV4-11 and Its STAT5 Signal Pathway / 中国实验血液学杂志

OBJECTIVE@#To investigate the effects of paclitaxel, quizartinib and their combination on proliferation, apoptosis and FLT3/STAT5 pathway of human leukemia cell line MV4-11 (FLT3-ITD+).@*METHODS@#MV4-11 cells were treated with paclitaxel and quizartinib at different concentrations for 24 h, 48 h and 72 h, respectively, and then the two drugs were combined at 48 h to compare the inhibition of proliferation, the apoptosis rate was detected by flow cytometry, the expression of FLT3 and STAT5 mRNA was determined by fluorescence quantitative PCR, and the protein expression of FLT3, p-FLT3, STAT5 and p-STAT5 was determined by Western blot.@*RESULTS@#Different combination groups of paclitaxel and quizartinib had synergistic inhibitory effect. The cell survival rate in the combination group was significantly lower than that in the single drug group (P<0.05). The cell apoptosis rate in the combination group was significantly higher than that in the single drug group (P<0.001). The expression of FLT3 mRNA in combination group was significantly higher than that in two single drugs (P<0.01). The expression of STAT5 mRNA in combination group was significantly higher than that in quizartinib group (P<0.001); increased compared with paclitaxel group, but there was no statistical significance. The expression level of p-FLT3、p-STAT5 protein in the combination group was significantly lower than that in the single drug group (P<0.05, P<0.05).@*CONCLUSION@#Paclitaxel combined with quizartinib can synergistically inhibit the proliferation of MV4-11 cell line and promote the apoptosis of MV4-11 cell line by inhibiting the activity of FLT3/STAT5 pathway.

Expression and Function of miR-99a-5p in Bone Marrow of Patients with MDS / 中国实验血液学杂志

OBJECTIVE@#To detect the expression of miR-99a-5p in myelodysplastic syndrome (MDS), to predict the target genes and to analyze its function by using bioinformatics.@*METHODS@#The expression levels of bone marrow miR-99a-5p in MDS patients were detected by qRT-PCR, and the correlation of miR-99a-5p expression with clinical pathological characteristics, percentage of marrow blasts , chromosome karyotype and peripheral blood hemogram were analyzed. The target genes of miR-99a-5p were predicted by Targetscan, Miranda and Microcosm, and the intersection of the predicted results of 3 softwares was used as a potential target gene for miR-99a-5p.@*RESULTS@#The expression level of bone marrow miR-99a-5p in MDS patients was significantly higher than that of healthy controls (P<0.01); According to the prognostic score of IPSS, MDS patients were divided into relatively low risk group (including low risk group and intermediate risk group 1) and relatively high risk group (including intermediate risk group 2 and high risk group). Analysis showed that the expression level of bone marrow miR-99a-5p in relatively low risk group was 2.40 times higher than that in healthy control group (P<0.01), the expression level of bone marrow miR-99a-5p in relatively high risk group was 6.66 times higher than that in healthy control group (P<0.01), the expression level of miR-99a-5p in relatively high risk group was 2.80 times higher than that in the relatively low risk group ( P<0.01) ; the expression level of bone marrow miR-99a-5p in t-MDS group was 6.35 times higher than that in healthy control group (P<0.001). There was a significant positive correlation between the expression level of miR-99a-5p and the percentage of marrow blasts (P<0.01), but the expression of miR-99a-5p did not correlate with chromosome karyotype and peripheral blood hemogram; In this study it was obtained that ST5 might participate in pathological mechanism of MDS by bioinformatic analyses and references.@*CONCLUSION@#The expression levels of miR-99a-5p is up-regulated in MDS patients, and its expression showed a rising tendency which may be involved in the pathogenesis of MDS by regulating target gene ST5.

Methylation status of γ-globin gene promoter in β-thalassemia major / 中国实验血液学杂志

This study was aimed to detect and identify the promoter CpG island methylation of γ-globin gene in peripheral blood mononuclear cells from patients with β-thalassemia major and healthy adult in Guangxi province, as well as to analyze the difference of promoter methylation rate of each CpG sites between them, and then to screen the promoter CpG island main methylation sites which maybe influence γ-globin expression. The template DNA was modified by bisulfite genomic sequencing PCR; the promoter sequences of γ-globin gene were amplified by technique Touchdown PCR, and then the PCR products were cloned and sequenced for obtaining methylation status of each CpG sites in target fragments, and then the accurate methylation sites and levels were detected quantitatively. The results indicated that the 4 CpG methylation sites locating at 28, 122, 231 and 234 bp in sequences were hypermethylated. As compared with healthy adults, the DNA methylation rate of 122 and 231 bp CpG sites in patients with β-thalassemia major was obviously lower, however, methylation rates of 28 and 234 bp sites were not significantly different between patients and healthy adults. It is concluded that the methylation sites 28, 122, 231 and 234 bp of γ-globin gene promoter are found both in patients with β-thalassemia major and healthy adults. The 122 and 231 bp sites are identified preliminarily to be involved in the regulation of γ-globin expression. This study provides the experimental evidence for alleviating the clinical symptoms of β-thalassemia major and targeting gene treatment through the regulation of γ-globin.

Effects of ligustrazine on expression of PECAM-1/CD31 and hematopoietic reconstitution in syngenic bone marrow transplantation of mice / 中国实验血液学杂志

To estimate the effect of ligustrazine on the expression of PECAM-1/CD31 and hematopoietic reconstitution in syngenic bone marrow transplanted mice, 56 BALB/c mice were divided into 3 groups: normal control group, BMT control group, ligustrazine treated group (BMT + Ligustrazine) and syngenic BMT mouse models were established according to the literatures. The BMT control group and the ligustrazine treated group were given orally 0.2 ml saline and 2 mg ligustrazine twice a day respectively. On days 7, 14, 21 after BMT, mice were killed and peripheral blood cells, bone marrow nucleated cells (BMNC) were detected. Histological observation of bone marrow was made and the CD31 expression was assayed by flow cytometry. The results showed that in ligustrazine treated group the peripheral blood cell, BMNC counts on days 7, 14, 21 after BMT were higher than in the BMT control group (P < 0.01 or P < 0.05). The expression of CD31 in ligustrazine treated group on days 7, 14, 21 after BMT was also higher than in the BMT control group (P < 0.01 or P < 0.05). In conclusion, ligustrazine enhances CD31 expression in bone marrow cells after syngenic bone marrow transplantation of mice, which may be related to the mechanisms underlying the ligustrazine accelerating hematopoietic reconstitution in syngeneic bone marrow transplantation.